There have been various types of electric heater devices provided for a variety of functions and one use of electric heater units is for heating the water in the beverage producer such as coffee pots, coffee percolators, and the like. A prior patent of ours, U.S. Pat. No. 3,767,898 shows one commercial type of an electric heater that has been particularly satisfactory in functioning effectively and efficiently for heating the liquid contents of containers to desired steaming temperatures. That heater included a high limit cut off thermostat positioned internally of the heater case. This prior unit functions to supply heat to the particular appliances when predetermined elevated temperatures above boiling are reached.
These prior units have had the characteristics that the temperature provided by the electric heater will raise the contents of the electrical appliance to boiling, then the thermostat would open only after all the water has boiled away and the heater then begins to heat rapidly to run away temperatures. In this manner, the thermostat prevents dry operation at elevated temperatures and thus protects the plastic components.
The prior patent relates to a steamer unit such as a clothes steamer while the present invention relates to a hot beverage maker.
In contrast, in some instances, especially when heating small quantities of water to produce coffee, cocoa or the like, it may be desired not to boil the water in the container as part of the beverage making process, and to provide controlled temperatures in the processed liquid.